Vortex blower

Abstract: A vortex blower includes an induction motor (1) and a blower portion (2) driven by the motor. The blower portion comprises an impeller (4) and a casing (8). The impeller is so mounted on a rotary output shaft (3) of the induction motor that the impeller is disposed near the induction motor. The casing is so disposed that the impeller is interposed between the induction motor and the casing. An inlet port (10) and an outlet port (11) are provided on an end of the casing opposite to the induction motor. The blower portion has approximately the same diameter as that of the induction motor.

Description: FIELD OF THE INVENTION AND RELATED ART STATEMENT The present invention relates to a vortex blower for blowing air. Such a vortex blower is e.g. disclosed in Japanese Unexamined Patent Publication No. 51-57011. A conventional vortex blower comprises a motor portion and a blower portion connected thereto. The blower portion includes an impeller driven by the motor portion and a casing comprising an annular groove interposed between the impeller and the motor portion. The impeller and the casing define therebetween an annular working chamber in which air is pressurized. In a vortex blower, it is necessary that an air inlet means and an air outlet means are communicated with an annular groove of the casing of the blower portion. Therefore, in the conventional formation, the inlet means and the outlet means radially extend outward, or extend along outside of the motor. As a result, an outer diameter of the entire blower is restricted by that of the casing which is larger than the motor portion, and reducing the size of the blower is difficult. A vortex blower including the features of the first part of claim 1 is known from GB-A-2 126 652. In Soviet Inventions Illustrated (Section PQ, Week 8639, 9 October 1986, Derwent Publications Ltd.) a compressor is described having a casing in which an air inlet and an air outlet are provided opposite to an impeller and said air inlet and said air outlet extend axially outwardly. SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact vortex blower layout. This object is met by a vortex blower according to claim 1. Preferred embodiments are disclosed in the depending claims. According to one aspect of the present invention, there is provided a vortex blower, which comprises a motor having an output rotary shaft, a casing having an annular groove, and an inlet means and an outlet means for working medium, both communicated with said annular groove, and an impeller having an annular groove in which a plurality of blades or vanes are provided to extend radially to separate the annular groove into a plurality of sections, the impeller being interposed between the motor and the casing, and the annular groove of the impeller being opposite to the annular groove of the casing to cooperate with each other to define therebetween a working chamber for the working medium, and the impeller being directly connected to and driven by the rotary shaft of the motor. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially cross-sectional view showing a first example of a vortex blower; Figs. 1A and 1B are cutaway cross-sectional views each showing a sectional configuration of an annular groove; Fig. 2 is a side view of Fig. 1 viewed from lines II - II; Fig. 3 is a partially cross-sectional view showing a conventional vortex blower; Fig. 4 is a partially cross-sectional view showing a first embodiment of the present invention; Fig. 5 is a partially cross-sectional view showing a second embodiment of the present invention; Fig. 6 is a side view of Fig. 5 viewed from the lines VI - VI; Fig. 7 is a partially cross-sectional view showing a third embodiment of the present invention; Fig. 8 is a side view of Fig. 7 viewed from the lines VIII - VIII; Fig. 9 is a partially cross-sectional view showing a second example of a vortex blower; Fig. 10 is a side view of Fig. 9 viewed from the lines X - X; Fig. 11 is a partially cross-sectional view showing a third example of a vortex blower; Fig. 12 is a side view of Fig. 11 viewed from the lines XII - XII; Fig. 13 is a partially cross-sectional view showing a fourth example of a vortex blower; Fig. 14 is a side view of Fig. 13 viewed from the lines XIV - XIV; Fig. 15 is a partially cross-sectional view showing a fifth example of a vortex blower. Fig. 16 is a side view of Fig. 15 viewed from the lines XVI - XVI; Fig. 17 is a partially cross-sectional view showing a sixth example of a vortex blower; Fig. 18 is a side view of Fig. 17 viewed from the lines XVIII - XVIII; Figs. 19 and 20 are front views each showing a mounting condition of a blower; Fig. 21 is a partially cross-sectional view showing a fourth embodiment of the present invention; Fig. 22 is a side view of Fig. 21 viewed from the lines XXII - XXII; Fig. 23 is a wiring diagram showing an invertor in Fig. 21; and Figs. 24 to 27 are partially cross-sectional views each showing another embodiment of the present invention. The examples shown in Figs. 1, 2, 3 and 9 to 20 do not fall within the scope of the attached claims and are therefore not embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figs. 1 and 2, an example for a vortex blower not within the scope of the present invention comprises a totally-enclosed induction motor 1 and a blower portion 2. The blower portion 2 includes an impeller 4 and a casing 8 formed by aluminum die-casting, respectively. The impeller 4 is directly mounted to the rotary shaft 3 of the induction motor 1 so as to be driven by the induction motor 1. The casing 8 is provided with a pressurizing passage 9. The pressurizing passage 9 is formed into annular shape around the center of rotation of the impeller 4, that is, the central axis C of the rotary shaft 3 of the motor 1, and is formed as a groove having a semi-circular sectional configuration. An annular groove 7 of the impeller 4 is the annular groove around the central axis C of the rotary shaft 3, and is separated into a plurality of sections in circumferential direction by a plurality of blades 5. The annular groove 7 presents a semi-circular sectional configuration. The impeller 4 is positioned on the rotary shaft 3 near the induction motor 1 and the casing 8 is positioned apart from the induction motor 1 and provided outside the impeller 4. The impeller 4 is rotatably fitted in the casing 8 to form an annular working chamber therebetween. The annular groove 7 of the impeller 4 is opened toward the opposite side of the induction motor 1 while the pressurizing passage 9 of the casing 8 is opened toward the induction motor 1. An inlet means 10 and an outlet means 11 communicated with the pressurizing passage 9 are formed at the edge face of the casing 8. The inlet means 10 and the outlet means 11 are provided toward the axial direction opposite to a direction toward the induct motor 1, that is, axially outward. Contrary to this, in the conventional vortex blower shown in Fig. 3, the impeller 104 is mounted on the rotary shaft 103 so that the opening of the annular groove 107 faces to the induction motor 101, and the casing 108 is mounted between the impeller 104 and the induction motor 101 so that the opening side of the pressurizing passage 109 faces to the impeller 104. Therefore, the inlet means 110 and the outlet means 111 communicated with the pressurizing passage 109 of the casing 108 radially extend outward of the induction motor 101, and the outer diameter of the entire blower can not be smaller, so that the outer diameter of the entire blower must be larger than the outer diameter of the casing, which is larger than that of the induction motor 101. According to the example of Figs. 1 and 2, the outer diameter of the blower portion 2 (casing 8) can be equal to that of the induction motor 1 because the inlet means 10 and outlet means 11 need not to be provided around the induction motor 1. Thus, a compact vortex blower may be easily obtained. According to the example of Figs. 1 and 2, the cover 12 used in the conventional example of Fig. 3 needs not to be additionally provided, and the casing 8 can be bolted directly to the induction motor 1 through the extended periphery thereof, thereby simplifying a formation of the blower. And, since the impeller 4 is fitted inside the casing 8, pressure leakage can be prevented. The sectional configuration of the annular groove 7 of the impeller 4 is not limited to a semicircle. The sectional configuration may be formed in a round shape to prevent occurrence of vortex flow of air at both bottom portions of the annular groove, for example, a semi-ellipse shape (Fig. 1A), and a shape with a straight bottom portion and two quarter-circular corner portions (Fig. 1B) or the like. The embodiment of Fig. 4 shows a cooling system for the entire vortex blower. When the impeller 3 of the blower portion 2 is rotated by the induction motor 1, a cooling fan 13 is also rotated and a flow of a cooling air F shown by an arrow in the drawing can be obtained by the action of an end cover 14. By this, the induction motor 1 and the blower portion are forcibly cooled and a temperature increase may be efficiently controlled. As is well known, the higher a rotary speed of the impeller may become, or the more an amount of the flow of air may be reduced at the inlet means 10 or the outlet means 11, the more an amount of air friction inside the blower is increased. Therefore, a heating value in the blower portion 2 is increased, and temperature of the equipment is apt to increase. In the embodiment of Figs. 5 and 6, cooling fins 15 are mounted to the casing 8 to increase the contact area of the casing 8 and air, and to pass the cooling air F through spaces formed between the casing and the cooling fins 15 as shown by an arrow in the drawing, thereby obtaining higher cooling effect. According to this embodiment, a temperature increase may be more sufficiently controlled. According to this embodiment, the cooling fins 15 are provided so as to extend not only to outer regions of the casing 8 but also to the edge face of the casing 8 opposite to that of the side of the induction motor 1, thereby efficiently increasing the contact area and easily obtaining a higher cooling effect. In the embodiment of Figs. 7 and 8, a casing cover 16 is mounted outside the casing 8 to cool the casing 8 more positively. The casing cover 16 forms an air guiding passage 17 for guiding the cooling air F to the edge face of the casing 8 opposite to that of the side of the induction motor 1, as shown by an arrow in the drawings. Therefore, the casing 8 may be efficiently cooled and the temperature increase due to a reduction of the size may be securely controlled. In this embodiment, the cooling fins 15 shown in the embodiment of Fig. 5 may be provided and combined with the casing cover 16 to obtain a cooling effect. The mounting means for a vortex blower will now be described. Referring to Figs. 9 and 10, in an example for a vortex blower not within the scope of the attached claims, the outer diameter of the blower portion 2 can be approximately the same as that of the induction motor 1. Therefore, as shown in the example of Fig. 6, when the vortex blower is mounted by means of a trapezoid bracket 18 provided on the induction motor 1, the blower portion 2 does not interfere with mounting. The position of the trapezoid bracket 18 mounted to the induction motor 1 may be selected to any positions in correspondence to the inlet means 10 and the outlet means 11 of the blower portion 2. Therefore, the position of the vortex blower may be varied in accordance with use conditions, thereby keeping equipment layout in a most favorable state. Figs. 11 and 12 show a further example not within the scope of the present invention in which mounting members 19 of female thread-stud type are provided at the edge face of the casing 8 of the blower portion 2. In case of a vertical installation of the vortex blower in which the rotary shaft 3 is perpendicular provided, provision of the mounting members 19 on the casing 8 of the blower portion 2 makes it possible to make the installation projected area of the vortex blower the same as that of a case when only the induction motor 1 is installed, together with a synergistic effect of the same outer diameters of the blower portion 2 and the induction motor 1. Therefore, according to this example, the vortex blower can be easily and advantageously applied to the case that there is no sufficient installation space. In this example, three mounting members are provided, but it is needless to say that the number of the mounting members is not limited to three. Figs. 13 and 14 show an example not within the scope of the present invention in which the mounting members 21 of female thread-stud type are provided on an end bracket 20 of the induction motor 1 opposite to the blower portion of the induction motor 1. This example offers the same benefit as that in the example of Figs. 11 and 12, and is effective to a case in which the vortex blower is turned upside down in relation to the installation location. Figs. 15 to 18 show examples not within the scope of the present invention in which L-shaped mounting members 22 or 23 are provided instead of the mounting members 19 of female thread-stud type. In these examples, mounting areas required for installation of the vortex blower are relatively larger than those in the examples of Figs. 11 to 14. However, these examples are effective to increase the degree of freedom for installing the vortex blower. The mounting situation of these vortex blowers in use condition will be described. Fig. 19 shows a case in which the vortex blower shown in Figs. 11 and 12 is mounted on the surface of an installation member A at a fixed angle with respect to a horizontal plane, and Fig. 20 shows a case in which the vortex blower shown in Figs. 13 and 14 is mounted on the surface of an installation member B perpendicular to a horizontal surface. In these cases, the induction motor 1 overhangs from the blower portion 2. However, such a vortex blower may be easily mounted by suitably selecting the size of the induction motor 1, strength of its housing, and strength of its connect portion with the blower portion 2. Therefore, the degree of freedom of the equipment layout may be further increased. The examples of mounting shown in Figs. 19 and 20 may be applied to the examples of Figs. 15 to 18, and the degree of freedom of the equipment layout may be increased. As factors for determining aerodynamic properties of the vortex blower, there may be mentioned the size and shape of the impeller 4, the shape of the casing 8, the area of the pressurizing duct 9, and the shape of the inlet means and the outlet means 11. Among them, as factors relating to static pressure of the vortex blower, there may be particularly mentioned the outer diameter of the impeller 4 and the rotary speed thereof. Therefore, when a higher discharge pressure and a larger volume of air are required, the rotary speed of the impeller 4 may be increased. In the embodiment of Figs. 21 and 22, frequency conversion is performed using an invertor 30 to increase frequency of power supplied to the induction motor 1 higher than that of a power source. Generally, the volume of air of the vortex blower is proportional to the rotary speed of the impeller, and the pressure is proportional to the square of the rotary speed. Thus, if the rotary speed is trebled, pressure equivalent to two times of the output of the induction motor 1, as compared with the conventional vortex blower, is obtained. In Fig. 23, when the frequency of a commercial power source AC is f (50 Hz or 60 Hz), the output frequency of the inverter 30 is 3f (150 Hz or 180 Hz). The inverter 30 and the vortex blower are formed as an integral unit. By this, in spite of using an inverter, the vortex blower may be operated as a single unit like a general vortex blower. As shown in Figs. 21 and 22, the inverter 30 is spaced apart from the housing of the induction motor 1 so that the flow of the cooling air F produced by the cooling fan 13 is not interrupted and that the inverter 30 itself is also cooled. The mounting position of the inverter 30 may be arbitrarily selected to eliminate restrictions due to a mounting situation at a place where the vortex blower is used. To obtain a high discharge pressure and a large volume of air, a direct current (DC) motor 50 instead of the induction motor 1, and a voltage controller 40 instead of the inverter 30 may be used, respectively (see Fig. 27). In this case, the number of revolution of the DC motor 50 may be increased by raising the voltage supplied to the DC motor 50 with the voltage controller 40, thereby obtaining a high discharge pressure and a large volume of air. Figs. 24 to 26 each show an embodiment in which the inverter 30 is installed inside an end cover 14 of the induction motor 1 to obtain a cooling effect. Fig. 24 shows an embodiment in which a cooling effect is obtained by utilizing an intake air of the cooling fan 13. Fig. 25 shows an embodiment in which a cooling effect is obtained by utilizing the cooling air F from the cooling fans 13. Fig. 26 shows an embodiment in which an axial fan is used as the cooling fan 13 instead of generally used mixed flow impeller to mount the inverter 30 on the end bracket 20 of the induction motor 1.

Claims: A vortex blower comprising: a motor means (1, 50) having an output rotary shaft (3); a casing (8) having an annular groove (9), and an inlet means (10) and an outlet means (11) for working medium, both being communicated with said annular groove, respectively; and an impeller (4) having an annular groove (7) in which a plurality of blades or vanes (5) are provided to extend radially to partition said annular groove of said impeller into a plurality of sections, said impeller being interposed between said motor means and said casing, and said annular groove of said impeller being opposite to said annular groove of said casing to cooperate with each other to define therebetween a working chamber for said working medium, and said impeller being directly connected to and driven by said rotary shaft of said motor means; wherein said impeller (4) is connected to one end of said rotary shaft at the outside of said motor means (1, 50), so as to be disposed between said motor means (1, 50) and said casing (8); characterised in that said motor means (1,50) is a totally-enclosed motor having an enclosure from which both ends of said rotary shaft (3) protrude; said motor means (1,50) has a cooling fan (13) at the other end of said output rotary shaft (3) outside of said enclosure and has an end cover (14) for covering said cooling fan (13) and for forming a flow of cooling air along the surface of said totally-enclosed motor means (1, 50); and said casing (8) has an outer diameter equal to that of said motor means (1, 50) and has an extended periphery toward said motor means (1, 50), so as to guide said flow of cooling air along the outer surface of said casing (8). A vortex blower according to claim 1, wherein said motor means includes a DC (direct current) motor (50) and a controller (40) for adjustment of a voltage of power to be supplied to said DC motor. A vortex blower according to claim 1, wherein said motor means includes an induction motor (1) and an inverter (30) for adjustment of a frequency of power to be supplied to said induction motor. A vortex blower according to claim 1, wherein said casing (8) has cooling fins (15) on the outer surface, wherein each of said cooling fins (15) is disposed so as to extend along an axial direction of said output rotary shaft (3) to pass said cooling air through spaces formed between said casing (8) and said cooling fins (15). A vortex blower according to claim 1, further comprising a casing cover (16), wherein said casing cover (16) is formed so as to cover the outer surface of said casing (8) and to form an air guiding passage (17) for guiding said cooling air to an edge face of said casing (8). A vortex blower according to claim 3, wherein said inverter (30) is installed in a passage of said cooling air.

Inventors: FUJIO MASAYUKI, HASEGAWA KENGO, ISHIDA FUMIAKI, KOBAYASHI KAZUO, FUJIO, MASAYUKI, HASEGAWA, KENGO, ISHIDA, FUMIAKI, KOBAYASHI, KAZUO
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1994
Main classification: F04D23
IPC codes: F04D29, F04D23, F04D25